Are blood ketones a better predictor than urine ketones of acid base balance in diabetic ketoacidosis?

The role of anion gap normalization time in the management of pediatric diabetic ketoacidosis

Introduction

Our aims were to determine whether anion gap normalization time (AGNT) correlates with risk factors related to the severity of diabetic ketoacidosis (DKA) in children, and to characterize AGNT as a criterion for DKA resolution in children admitted with moderate or severe disease.

Methods

A ten-year retrospective cohort study of children admitted to the intensive care unit with DKA. We used a survival analysis approach to determine changes in serum glucose, bicarbonate, pH, and anion gap following admission. Using multivariate analysis, we examined associations between patients' demographic and laboratory characteristics with delayed normalization of the anion gap.

Results

A total of 95 patients were analyzed. The median AGNT was 8 h. Delayed AGNT (>8 h) correlated with pH < 7.1 and serum glucose >500 mg/dL. In multivariate analysis, glucose >500 mg/dL was associated with an increased risk for delayed AGNT, by 3.41 fold. Each 25 mg/dL elevation in glucose was associated with a 10% increment in risk for delayed AGNT. Median AGNT preceded median PICU discharge by 15 h (8 vs. 23 h).

Discussion

AGNT represents a return to normal glucose-based physiology and an improvement in dehydration. The correlation observed between delayed AGNT and markers of DKA severity supports the usefulness of AGNT for assessing DKA recovery.

Test validation, method comparison and reference range for the measurement of β-hydroxybutyrate in peripheral blood samples

Introduction

The measurement of β-hydroxybutyrate (βOHB) concentrations is a corner stone of the diagnosis of diabetic ketoacidosis and other ketonic states. The aim of this study was to perform a validation of a peripheral blood βOHB assay (Randox) on a Roche cobas c502 analyser and to establish a βOHB reference range for the validated assay.

Materials and methods

Precision, linearity and limit of detection and blank (LoD, LoB) were determined according to Clinical and Laboratory Standards Institute (CLSI) EP05-A3, EP 06-A and EP17-A2 guidelines, using commercial control material and residual patient sample pools. As method comparison, for 190 semi-quantitative measurements of urine ketones we determined the corresponding βOHB blood concentration. The reference range was based on the CLSI C28-A3 guideline, using 304 randomly selected serum samples from population based German National Cohort (GNC) study.

Results

Coefficients of variation for the validated assay ranged from 1.5% for high concentrations (3.1 mmol/L) to 6.5% for low concentrations (0.1 mmol/L). Detection capacity was LoB = 0.011 mmol/L and LoD = 0.037 mmol/L. Linearity of the assay ranged from 0.10 to 3.95 mmol/L. The agreement between the semi-quantitative urine ketone test and the βOHB blood test was moderate (Kappa = 0.66). The obtained 95% serum reference range was estimated as 0.02 to 0.28 mmol/l βOHB.

Conclusions

The Ranbut βOHB assay showed good precision and analytical performance. Our results confirm that βOHB measurement in peripheral blood is indeed a preferable alternative to the semi-quantitative measurement of urine ketones.

Pregnancy Ketonemia and Development of the Fetal Central Nervous System

Glucose is the major source of energy for the human brain which in turn uses ketone bodies as a supplement for energy deficit in glucose cell deficiency conditions. Pregnancy complicated by gestational diabetes is a condition associated with significantly increased risk of ketonemia development. The data available proves a changing influence of ketones on the central nervous system during fetal life and in adults as well. Ketone bodies freely pass through the placenta. They can affect fetal growth and organ damage development, especially the central nervous system. As agreed in the current recommendation of the diabetes associations, it is not obligatory for the attending doctor to conduct a routine inspection of ketone bodies during diabetes treatment in pregnancy. This article is a literature review of ketones' effect on the central nervous system and an attempt to initiate discussion whether we should consider including ketonemia assessment into the standard care package for pregnant women with diabetes and begin some research on the explanation of its influence on fetal development.

Evaluation of the Accuracy of Capillary Hydroxybutyrate Measurement Compared with Other Measurements in the Diagnosis of Diabetic Ketoacidosis: A Systematic Review

A complication of diabetes is diabetic ketoacidosis (DKA), which if left untreated is a life threatening condition. Prompt and accurate diagnosis of DKA is required for the commencement of life saving interventions. Measurements of ketone bodies in DKA have usually been through nitroprusside urine acetoacetate testing. The aim of this systematic review was to examine whether capillary β-hydroxybutyrate (β-OHB) testing is more accurate compared to other diagnostic methods of DKA. The following electronic databases were searched: EBSCO Host, MEDLINE, PSYCHInfo, CINAHL and Science Direct for publications from 1 January 2005 and up to and including 1 January 2016. Inclusion criteria were: Adults 18 years and over and known type 1 or type 2 diabetes. Retrospective and prospective observation studies were included. A total of nine studies met the inclusion criteria. Capillary β-OHB was found to have high sensitivity, specificity, positive predictive value and negative predictive value in identifying DKA compared to urinary ketone testing.

Utility of ketone measurement in the prevention, diagnosis and management of diabetic ketoacidosis

Ketone measurement is advocated for the diagnosis of diabetic ketoacidosis and assessment of its severity. Assessing the evidence base for ketone measurement in clinical practice is challenging because multiple methods are available but there is a lack of consensus about which is preferable. Evaluating the utility of ketone measurement is additionally problematic because of variability in the biochemical definition of ketoacidosis internationally and in the proposed thresholds for ketone measures. This has led to conflicting guidance from expert bodies on how ketone measurement should be used in the management of ketoacidosis. The development of point-of-care devices that can reliably measure the capillary blood ketone β-hydroxybutyrate (BOHB) has widened the spectrum of applications of ketone measurement, but whether the evidence base supporting these applications is robust enough to warrant their incorporation into routine clinical practice remains unclear. The imprecision of capillary blood ketone measures at higher values, the lack of availability of routine laboratory-based assays for BOHB and the continued cost-effectiveness of urine ketone assessment prompt further discussion on the role of capillary blood ketone assessment in ketoacidosis. In the present article, we review the various existing methods of ketone measurement, the precision of capillary blood ketone as compared with other measures, its diagnostic accuracy in predicting ketoacidosis and other clinical applications including prevention, assessment of severity and resolution of ketoacidosis.

Blood β-hydroxybutyrate vs. urine acetoacetate testing for the prevention and management of ketoacidosis in Type 1 diabetes: a systematic review

AIM

Diabetic ketoacidosis is a life-threatening complication of Type 1 diabetes. Blood β-hydroxybutyrate testing is now widely available as an alternative to urine acetoacetate testing for detecting ketosis. The aim of this study was to review the effectiveness of capillary or serum β-hydroxybutyrate compared with urine acetoacetate testing in prevention and management of diabetic ketoacidosis.

METHODS

MEDLINE, EMBASE, EBM Reviews, The Cochrane Library and CINAHL (until April 2012, no language restrictions, studies in humans) were searched for experimental and observational studies comparing the effectiveness of blood β-hydroxybutyrate and urine acetoacetate testing. Outcomes examined were prevention of diabetic ketoacidosis, time to recovery from diabetic ketoacidosis, healthcare costs and patient or caregiver satisfaction. Additional sources included reference lists, conference proceedings and contact with experts in the field.

RESULTS

Four studies (two randomized controlled trials and two cohort studies) met eligibility criteria, including 299 participants across 11 centres. Risk of bias was low to moderate. Blood ketone testing compared with urine testing was associated with reduced frequency of hospitalization (one study), reduced time to recovery from diabetic ketoacidosis (three studies), cost benefits (one study) and greater satisfaction (one study, intervention group only). No study assessed prevention of diabetic ketoacidosis. Meta-analysis could not be performed because of heterogeneity in study design and published data.

CONCLUSIONS

There is evidence suggesting that blood β-hydroxybutyrate testing is more effective than urine acetoacetate testing in reducing emergency department assessment, hospitalization and time to recovery from diabetic ketoacidosis, as well as potentially lowering healthcare expenditure. Further research in both young people and adults is needed.